Recent consumer interest in personal health has led to a variety of personal health monitoring devices being offered on the market. Such devices, until recently, tended to be complicated to use and typically had few features and responded slowly.
Recent advances in sensor, electronics, and power source miniaturization have allowed the size of personal health monitoring devices, also referred to herein as “biometric tracking” or “biometric monitoring” devices, to be offered in small sizes that were previously impractical. For example, the Fitbit Ultra is a biometric monitoring device that is approximately 2″ long, 0.75″ wide, and 0.5″ deep; it has a pixelated display, battery, sensors, wireless communications capability, power source, and interface button, as well as an integrated clip for attaching the device to a pocket or other portion of clothing, packaged within this small volume.
In some versions of personal health monitoring devices, GPS capabilities have been provided. Because GPS is a technology that was originally developed in the 1970s and 1980s to allow nuclear ballistic missile submarines to precisely know their locations in order to accurately target submarine-launched nuclear warheads, GPS does not always lend itself well to integration into modern consumer electronic devices. For example, by modern standards, the GPS system uses a very slow data transfer speed of 50 bits per second, which means that a GPS receiver, in some cases, has to be on for as long as 12 minutes before a GPS positional fix may be obtained. Once a positional fix is obtained, subsequent positional fixes may take much less time to obtain (assuming that the subsequent positional fix occurs within a sufficiently close interval), but this initial lock-on period requires that the GPS receiver be powered for the entire initial lock-on, which can be taxing on devices with small battery capacities.